Taisei Tanaka, Yoshinobu Konishi, Hiroshi Ichise, Shinya Tsukiji, Michiyuki Matsuda, Kenta Terai (2021) A Dual Promoter System to Monitor IFN-gamma Signaling in vivo at Single-cell Resolution., Cell structure and function, Volume 46, Number 2, pp. 103-111
Published in 2021 Dec 22 (Electronic publication in Nov. 6, 2021, midnight )
(Abstract) IFN-gamma secreted from immune cells exerts pleiotropic effects on tumor cells, including induction of immune checkpoint and antigen presentation, growth inhibition, and apoptosis induction. We combined a dual promoter system with an IFN-gamma signaling responsive promoter to generate a reporter named the interferon sensing probe (ISP), which quantitates the response to IFN-gamma by means of fluorescence and bioluminescence. The integration site effect of the transgene is compensated for by the PGK promoter-driven expression of a fluorescent protein. Among five potential IFN-gamma-responsive elements, we found that the interferon gamma-activated sequence (GAS) exhibited the best performance. When ISP-GAS was introduced into four cell lines and subjected to IFN-gamma stimulation, dose-dependency was observed with an EC50 ranging from 0.2 to 0.9 ng/mL, indicating that ISP-GAS can be generally used as a sensitive biosensor of IFN-gamma response. In a syngeneic transplantation model, the ISP-GAS-expressing cancer cells exhibited bioluminescence and fluorescence signals in an IFN-gamma receptor-dependent manner. Thus, ISP-GAS could be used to quantitatively monitor the IFN-gamma response both in vitro and in vivo.Key words: in vivo imaging, tumor microenvironment, interferon-gamma, dual promoter system.(MeSH Terms)